C + + Implementation Date Class

#include <iostream>using namespace std;class date{public:date (int year,int month , Int day): _year (year), _month (month), _day (day) {    if (year<1900| | month<1| | month>12| | day<1| | Day>getmonthday (year,month)) cout<< "Invalid date" &LT;&LT;ENDL;} Bool isleapyear (Int year)//To determine whether it is a leap year {   return  (year%4==0&&year%100!=0| | year%400==0);}     int getmonthday (int year,int month)//Gets the number of days per month {int montharr[12]={ 31,28,31,30,31,30,31,31,30,31,30,31};if (Isleapyear (year) &&month==2) {    return  montharr[month-1]+1;} ELSERETURN&NBSP;MONTHARR[MONTH-1];} date operator+ (Int day)//date + days {  date tmp (*this);  tmp._day +=day;   while (Tmp._day >getmonthday (tmp._year ,tmp._month ))   {       tmp._day -=getmonthday (Tmp._year ,tmp._month );   if (tmp._month ==12)   {       tmp._year  +=1;   tmp._month =1;  }  else  {       tmp._month +=1;  }  }  return tmp;} date operator-(Int day)//date-days {  date tmp (*this);  tmp._day -=day;   while (tmp._day <0)   {      tmp._day = Getmonthday (tmp._year ,tmp._month )-(-tmp._day)  ;  if (tmp._month ==1)    {       tmp._year -=1;   tmp._month =12;   }  else  {      tmp._month -=1;   }  }  return tmp;} int operator-(CONST&NBSP;DATE&AMP;&NBSP;D)//date minus date {     int countday=0;  int&nbsP;countmonth=0; int countyear=0; date tmp (*this);  if (_day<d._day )  {      countday=_day+getmonthday (D._year,d._month)-d._day ; _month=_month-1;  } else {      countday=_day-d._day ; }  if (_ month<d._month )  {     while (_month)  {      countmonth+=getmonthday (_year,_month); _month--; } int n=12-d._month; while (n)  {  date tmp (*this);       countmonth+=getmonthday (d._year ,d._month+ n-1 );  n -- ; } _year=_year-1; }  else  {  Int n=_month-d._month;     while (n)  {       Countmonth+=getmonthday (d._year ,d._month+n-1 );  n--; }  }  if ( Isleapyear (d._year))  {&nbsP;   countyear= (_year-d._year ) *366; } else {       countyear= (_year-d._year ) *365; }return countday+countmonth+countyear;} Void display () {    cout<<_year<< "-" <<_month<< "-" <<_day <<endl;} private:int _year;int _month;int _day;}; Void test1 () {    date d1 (2015,1,16);d 1. display  ();//(D1+34). display  ();(d 1-30). display  ();} Void test2 () {   date d1 (2015,11,13);    d1. display  ();    date d2 (2015,10,13);    d2. display  ();     cout<<d1-d2<<endl;//Date-Date}int main () {Test2 (); System (" Pause ");     return 0;}

C + + Implementation Date Class